The service life of the seal and of the rolling bearing of a pump shaft depends on the temperature. With an increasing temperature of the medium to be delivered by the pump--for example hot oil at 350.degree. C.--increasing requirements are placed on the temperature resistance or cooling of the seal and bearing housing. It is known (EP-A 535365) to arrange the seal housing of a centrifugal pump for delivering hot media at an axial distance from the pump housing, to arrange the drive-side shaft bearing at a distance from the bearing housing and to provide a fan on the shaft in the spacing between the shaft bearing and the seal housing, which fan sucks in ambient air and drives it in the direction towards the pump axially over the surface of the seal housing in order to cool the latter. This flow direction is plausible because the flow leaving the fan wheel has a higher speed than the intake flow, and because the air flow heated by the seal housing and the pump surface is conducted away from the drive motor which is sensitive to temperature and is arranged on the other side of the bearing housing. Since it is undesirable also to cool the pump by means of the air flow, in the known pump a thermal insulation device is provided on the side of the pump facing the air flow.
In another known pump (GB-B-998313), air is fed to a heat exchanger by the fan located between the seal and the drive motor, which heat exchanger provides the seal with cooled liquid. The air sucked in by the fan brushes along the end face of the seal housing facing the motor and cools the said seal housing. Since the cooling effect is based primarily on the cooling liquid fed directly to the seal, no devices are provided which ensure intensive air cooling of the seal housing.